Ethylene/vinyl acetate latex binders and paints which are free of volatile coalescents and freeze-thaw additives

Abstract

The invention is directed to aqueous coating compositions which are freeze-thaw stable in the absence of conventional volatile coalescing solvents and volatile freeze-thaw (F/T) additives and which utilize a latex binder which contains an EVA thermoplastic interpolymer which is prepared by emulsion polymerization of ethylene, vinyl acetate and a monomer represented by structure (I) where R is hydrogen or a methyl group, X is O or NH, and n is an integer from 1 to 11 and to the latex binder which contains the EVA interpolymer.

We claim: 
     
       1. A latex binder, comprising: (a) a thermoplastic polymer present in amounts effective to function as a binder and film-former in a latex paint which employs the latex, said polymer consisting essentially of the emulsion polymerization product of: (i) about 60 pphm to about 90 pphm of vinyl acetate,   (ii) about 10 pphm to about 25 pphm of ethylene; and   (iii) 0.05 to about 1.0 pphm of a monomer represented by Structure I ##STR3## wherein R is H or CH 3 , X is O or NH and n is an integer from 1 to 11; (b) water; and     (c) an emulsifier system present in amounts effective to disperse the polymer in the water, wherein said emulsifier system is comprised of greater than 60 weight percent of a nonionic emulsifier and less than 40 weight percent of an anionic emulsifier, based on total weight of the nonionic emulsifier and the anionic emulsifier.   
     
     
       2. The latex binder according to claim 1 wherein the thermoplastic polymer is prepared by emulsion polymerization of from about 70 pphm to about 90 pphm of the vinyl acetate monomer, from about 10 pphm to about 20 pphm of the ethylene monomer; and from about 0.1 pphm to about 0.8 pphm of the monomer represented by Structure I. 
     
     
       3. The latex binder according to claim 2 wherein the thermoplastic polymer is prepared by emulsion polymerization of from about 80 pphm to about 90 pphm of the vinyl acetate monomer, from about 10 pphm to about 15 pphm of the ethylene monomer; and from about 0.15 pphm to about 0.6 pphm of the monomer represented by Structure I. 
     
     
       4. The latex binder according to claim 1 wherein the emulsifier system is comprised of greater than 80 weight percent of the nonionic emulsifier and less than 20 weight percent of an anionic emulsifier, based on the total weight of the nonionic emulsifier and the anionic emulsifier.